UC3845

更新时间： 2024-11-22 21:57:39

品牌	Logo	应用领域
德州仪器 - TI		控制器
页数	文件大小	规格书
8页	436K
描述
Current Mode PWM Controller

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数据手册
替代型号

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UC3845 数据手册

UC1842/3/4/5

UC2842/3/4/5

UC3842/3/4/5

Current Mode PWM Controller

FEATURES

DESCRIPTION

•

Optimized For Off-line And DC

To DC Converters

The UC1842/3/4/5 family of control ICs provides the necessary features to im-

plement off-line or DC to DC fixed frequency current mode control schemes

with a minimal external parts count. Internally implemented circuits include un-

der-voltage lockout featuring start up current less than 1mA, a precision refer-

ence trimmed for accuracy at the error amp input, logic to insure latched

operation, a PWM comparator which also provides current limit control, and a

totem pole output stage designed to source or sink high peak current. The out-

put stage, suitable for driving N Channel MOSFETs, is low in the off state.

•

Low Start Up Current (<1mA)

Automatic Feed Forward

Compensation

•

Pulse-by-pulse Current Limiting

Enhanced Load Response

Characteristics

Differences between members of this family are the under-voltage lockout

thresholds and maximum duty cycle ranges. The UC1842 and UC1844 have

UVLO thresholds of 16V (on) and 10V (off), ideally suited to off-line applica-

tions. The corresponding thresholds for the UC1843 and UC1845 are 8.4V

and 7.6V. The UC1842 and UC1843 can operate to duty cycles approaching

100%. A range of zero to 50% is obtained by the UC1844 and UC1845 by the

addition of an internal toggle flip flop which blanks the output off every other

clock cycle.

•

Under-voltage Lockout With

Hysteresis

•

Double Pulse Suppression

High Current Totem Pole

Output

•

Internally Trimmed Bandgap

Reference

•

500khz Operation

Low RO Error Amp

BLOCK DIAGRAM

Note 1: A/B A = DIL-8 Pin Number. B = SO-14 Pin Number.

Note 2: Toggle flip flop used only in 1844 and 1845.

4/97

12 3 4 5 6 7 8

中文翻译

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UC3845 替代型号

型号	品牌	替代类型	描述	数据表
LM5021-Q1	TI	功能相似	LM5021-Q1 AC-DC Current-Mode PWM Controller
LM5021	TI	功能相似	LM5021 AC-DC Current Mode PWM Controller

与UC3845相关器件

型号	品牌	获取价格	描述	数据表
UC3845_15	UTC	获取价格	HIGH PERFORMANCE CURRENT MODE PWM CONTROLLERS
UC3845A	TI	获取价格	Current Mode PWM Controller
UC3845A	FCI	获取价格	High Performance Current Mode Controller
UC3845A	STMICROELECTRONICS	获取价格	HIGH PERFORMANCE CURRENT MODE PWM CONTROLLER
UC3845A	MICROSEMI	获取价格	CURRENT MODE PWM CONTROLLER
UC3845A-BW	FCI	获取价格	Current Mode PWM Controller Low Start-Up and Operating Current
UC3845ACD	FCI-CONNECTOR	获取价格	Switching Regulator/Controller
UC3845ACS	FCI-CONNECTOR	获取价格	Switching Regulator/Controller
UC3845AD	MICROSEMI	获取价格	CURRENT MODE PWM CONTROLLER
UC3845AD	TI	获取价格	Current Mode PWM Controller